846
FXUS62 KCHS 172354
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
754 PM EDT SUN MAY 17 2026
WHAT HAS CHANGED
ALL SECTIONS HAVE BEEN UPDATED.
KEY MESSAGES
- 1) FEW TO SCATTERED SHOWERS WITH AN ISOLATED STRONG THUNDERSTORM
POSSIBLE ACROSS INTERIOR SOUTHEAST GEORGIA THIS AFTERNOON.
- 2) MINOR COASTAL FLOODING EXPECTED ALONG PORTIONS OF THE SOUTHEAST
SOUTH CAROLINA COAST WITH THE EVENING HIGH TIDE CYCLES TODAY
AND MONDAY.
- 3) MOSTLY DRY CONDITIONS EXPECTED THROUGH MIDWEEK WITH INCREASING
RAIN CHANCES TO OCCUR LATE WEEK.
DISCUSSION
KEY MESSAGE 1: FEW TO SCATTERED SHOWERS WITH AN ISOLATED STRONG
THUNDERSTORM POSSIBLE ACROSS INTERIOR SOUTHEAST GEORGIA THIS
AFTERNOON.
HIGH PRESSURE EXTENDING ACROSS THE WESTERN ATLANTIC WILL MAINTAIN A
STRONG INFLUENCE ON THE REGION TODAY AS MID-UPPER RIDGING PREVAILS
ALOFT. THE BULK OF GUIDANCE CONTINUES TO SHOW A PRONOUNCED NORTHWEST-
SOUTHEAST ORIENTED THETA-E AXIS SETTING UP FROM EAST-CENTRAL
GEORGIA INTO FAR SOUTHEAST GEORGIA THIS AFTERNOON, WITH MLCAPE
APPROACHING 2500-3000 J/KG DURING PEAK DIURNAL HEATING. INSTABILITY
COULD SUPPORT FEW TO SCATTERED SHOWERS ALONG WITH THUNDERSTORMS
LATER THIS AFTERNOON WHILE H5 VORT ENERGY ROUNDS THE WESTERN
PERIPHERY OF THE ATLANTIC HIGH NEAR THE TIMING OF AN INLAND MOVING
SEA BREEZE. HOWEVER, DEEP-LAYER SHEAR IS WEAK, SUGGESTING LITTLE
ORGANIZATION TO CONVECTION, UNLESS ACTIVITY CONGEALS AND/OR OUTFLOW
BOUNDARY INTERACTIONS GIVE A TEMPORARY BOOST TO THUNDERSTORMS ALONG
AND/OR JUST AHEAD OF A SEA BREEZE ACROSS FAR INTERIOR OF SOUTHEAST
GEORGIA.
ALTHOUGH MOST CONVECTION THAT MATERIALIZES IS EXPECTED TO REMAIN IN
THE FORM OF GENERAL SHOWER AND THUNDERSTORM ACTIVITY AND JUST INLAND
TO THE LOCAL AREA TODAY, A STRONGER THUNDERSTORM CAN NOT BE RULED
OUT IF THE TIMING OF CONVECTION ALIGNS WITH THE SEA BREEZE PASSAGE
MID-LATE AFTERNOON ACROSS FAR INTERIOR SOUTHEAST GEORGIA. ALTHOUGH A
RISK FOR HAIL IS PRESENT WITH MID-LVL LAPSE RATES NEAR 7 C/KM AND
LARGE -10C TO -30C CAPE IN PLACE, DEEP LAYER SHEAR IS WEAK UNDER THE
SYNOPTIC HIGH AND THE ENVIRONMENT MORE SUPPORTIVE OF SMALL HAIL IF
REALIZED. GUSTY WINDS WILL BE THE PRIMARY CONCERN WITH A STRONGER
THUNDERSTORM GIVEN 8-8.5 C/KM LOW-LVL LAPSE RATES AND DCAPE AROUND
1000 J/KG DURING PEAK HEATING OF THE DAY. THE STORM PREDICTION
CENTER DOES HIGHLIGHT FAR INTERIOR SOUTHEAST GEORGIA IN A MARGINAL
RISK FOR SEVERE WEATHER TODAY, BUT THE THREAT REMAINS QUITE
CONDITIONAL AND MORE LIKELY JUST INLAND TO THE LOCAL AREA BASED ON
ACTIVITY DEVELOPING AHEAD OF A SEA BREEZE AND ALONG THE WESTERN EDGE
OF THE ATLANTIC HIGH PRIOR TO SUNSET.
KEY MESSAGE 2: MINOR COASTAL FLOODING EXPECTED ALONG PORTIONS OF THE
SOUTHEAST SOUTH CAROLINA COAST WITH THE EVENING HIGH TIDE CYCLES
TODAY AND MONDAY.
ASTRONOMICAL INFLUENCES ASSOCIATED WITH THE NEW MOON (5/16) AND
LUNAR PERIGEE (5/17) ALONG WITH A MODEST SOUTHEASTERLY ONSHORE FLOW
WILL CONTINUE TO DRIVE ELEVATED TIDE LEVELS EARLY THIS WEEK, LEADING
TO MINOR COASTAL FLOODING ALONG THE SOUTHEAST SOUTH CAROLINA COAST
AND POTENTIALLY ALONG THE SOUTHEAST GEORGIA COAST. THE GREATEST RISK
FOR MINOR COASTAL FLOODING WILL BE AT THE CHARLESTON HARBOR TIDE
GAGE, WHILE A MUCH LOWER POTENTIAL EXISTS AT FORT PULASKI. THE
LATEST FORECAST ADVERTISES A PEAK HIGH TIDE AROUND 7.1 TO 7.3 FT
MLLW IN THE CHARLESTON HARBOR THIS EVENING, THEN 7.0 TO 7.2 FT MLLW
MONDAY EVENING. A COASTAL FLOOD ADVISORY HAS THEREFORE BEEN ISSUED
FOR COASTAL COLLETON AND CHARLESTON COUNTIES BETWEEN 7 PM TO 11 PM
THIS EVENING. ADDITIONAL COASTAL FLOOD ADVISORIES COULD BE NEEDED
MONDAY. ASTRONOMICAL TIDE LEVELS THEN BEGIN TO FALL AND THE
POTENTIAL FOR MINOR COASTAL FLOODING WILL DIMINISH.
KEY MESSAGE 3: MOSTLY DRY CONDITIONS EXPECTED THROUGH MIDWEEK WITH
INCREASING RAIN CHANCES TO OCCUR LATE WEEK.
SURFACE HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH MIDWEEK,
WHILE RIDGING LARGELY PREVAILS ALOFT. CONVECTION POTENTIAL WILL BE
QUITE LIMITED, WITH MOST AREAS STAYING DRY MONDAY THROUGH WEDNESDAY.
BEYOND WEDNESDAY, THE PATTERN COULD BECOME MORE ACTIVE, ALTHOUGH
THERE IS STILL A GOOD BIT OF INCONSISTENCY BETWEEN MODELS. SHORTWAVE
ENERGY WILL ADVANCE TOWARD THE AREA, BUT WILL COMPETE WITH THE DEEP
BERMUDA HIGH OFFSHORE, WHICH COULD DEFLECT THE BETTER FORCING NORTH
OF THE REGION. AT THE SURFACE, A COLD FRONT WILL APPROACH THE AREA,
WITH ITS EVENTUAL PROGRESSION LIKELY DEPENDENT ON THE STRENGTH OF
THE RIDGE. OUR CURRENT FORECAST INDICATES A SLOW PROGRESSION OF THE
FRONT INTO SOUTHEAST SC/GA OVER THE COURSE OF SEVERAL DAYS (THU-
SAT), WHICH WOULD SUPPORT INCREASING MOISTURE AND HIGHER RAIN
CHANCES ACROSS THE AREA. HOWEVER, IF THE RIDGE REMAINS STRONGER, THE
FRONT AND BETTER FORCING COULD REMAIN FARTHER TO THE WEST AND NORTH,
RESULTING IN LOWER RAIN CHANCES THAN CURRENTLY FORECAST. ENSEMBLE
MEAN INDICATES THE PROBABILITY FOR ACCUMULATED RAINFALL OF >1"
ENDING SATURDAY EVENING OF ONLY 10-40% (HIGHEST INLAND), SO
WIDESPREAD SIGNIFICANT RAINFALL SEEMS UNLIKELY AT THIS TIME.
AVIATION /00Z MONDAY THROUGH FRIDAY/
VFR CONDITIONS WILL PREVAIL AT CHS/JZI/SAV TERMINALS THROUGH 0Z
TUESDAY. HOWEVER, GUSTY WINDS (14-17 KT) WILL ACCOMPANY THE
AFTERNOON SEA BREEZE ON MONDAY.
EXTENDED AVIATION OUTLOOK: THERE ARE NO HIGH CONFIDENCE
CONCERNS.
MARINE
TODAY AND TONIGHT: HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER
FEATURE ACROSS LOCAL WATERS THROUGHOUT THE DAY AND NIGHT, RESULTING
IN A TYPICAL SUMMER-LIKE SOUTHERLY FLOW REGIME. IN GENERAL, WIND
SPEEDS WILL BE NO HIGHER THAN 10 KT ACROSS MOST WATERS, ALTHOUGH
LOCALIZED ENHANCEMENT ALONG THE LAND/SEA INTERFACE AND CHARLESTON
HARBOR IS ANTICIPATED WITH ANY SEA BREEZE ENHANCED THIS AFTERNOON
(~15 KT). SEAS SHOULD RANGE BETWEEN 2-4 FT, LARGEST BEYOND 20 NM
FROM THE COAST OVERNIGHT.
MONDAY THROUGH FRIDAY: NO MARINE CONCERNS ARE EXPECTED. HIGH
PRESSURE TO THE EAST WILL DRIVE ONSHORE EAST-SOUTHEASTERLY FLOW EACH
DAY, WITH WIND SPEEDS MOSTLY TOPPING OUT IN THE 10-15 KNOT RANGE.
EACH AFTERNOON AND EVENING THERE COULD BE SOME LOCAL ENHANCEMENT
ALONG THE LAND/SEA INTERFACE WITH THE DIURNAL SEA BREEZE. SEAS
SHOULD AVERAGE 2-4 FEET THROUGH THE PERIOD.
RIP CURRENTS: THE COMBINATION OF INFLUENCES FROM THE NEW MOON CYCLE
AND PERSISTENT ONSHORE FLOW WILL PRODUCE AN ELEVATED RISK OF RIP
CURRENTS THROUGH MIDWEEK. A MODERATE RISK OF RIP CURRENTS IS IN
EFFECT AT ALL SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA BEACHES
MONDAY AND TUESDAY.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...COASTAL FLOOD ADVISORY UNTIL 11 PM EDT THIS EVENING FOR SCZ149-
150.
MARINE...NONE.
NED
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